Joey as much as I love you the higher voltage tap argument is not weak. When you have 11.8 volts at your homerun and you lose a 35 watt lamp you are in trouble on a long distant run with a higher than 15v tap. You are going to lose those other lamps very soon if you don't change that burnout immediately. Lamps were made to operate at 12v . They don't last very long at 12.5v and higher.

Pete, hey Buddy I'm a big fan and I am happy to set the record strait on this topic today and I will be setting the record straight on the NEC, UL 1838, 506, 1571, 1593, 2108, and the non existent 5058, as well as Voltage Drop..

I have sat back for my whole lighting career and watched how the industry has evolved and has ceased to evolve. There is no identity to this lighting industry. We as contractors sit here and have been taught by who? Yourself, a book that you cannot understand because you have no foundation, a manufacturer that has never installed a lighting job in their life...............I'm just about ready to get side tracked so back on point.

Increased Voltage to Lamps Above 12

FACT: you have 2 light bulbs @ about 100ft and you are using the 15v tap. This means you have a 3 volt drop shared between 2 fixtures, 1.5v per lamp. When one lamp burns out the other lamp will have 13.5v. At 13.5v the lamp life is dramatically reduced from 100% to 21% life which is 855 hours. If you had 15 volts at the lamp your life at the lamp is reduced to 5% of lamp life 215 hours. Above 15 volt.................what does it matter,.............fact is anything above 12 volts kills the lamp life.

THERE IS NO DIFFERENCE BETWEEN 13.14.15.16.17.18.19.20.OR 22 IT IS EXPONENTIAL EVEN AT 12.5 VOLTS THE LAMP LIFE IS 59% OF RATED LIFE. This is where it all gets back to proper wiring design.( more on this later)

So your right the higher the voltage the faster the lamp burns out. whether it burns out within 1 month or anything less it just does not matter.

I just have to say this, it is the NEC that is mandated across the US (and almost every other country), it is the bible when it comes to electricity NOT UL! Article 411 states 30v or less not 15. There is no need to discuss this further although I know it is going to be (please find me one job that has been turned down in the US, 10's of thousands of inspectors cant be wrong). If any of you wish to discuss this further I am more than willing to pay for a conference call and discuss this with great dialog.